Ocular collar stent for treating narrowing of the irideocorneal angle

ABSTRACT

An ocular stent for insertion in an anterior chamber of an eye is provided. The stent facilitates the restoration of the structure of an irideocorneal angle of the anterior chamber for treating structural changes from ocular aging. The stent includes an annular body sized to fit in the irideocorneal angle of the eye. The body includes: an anterior portion configured to contact a surface of a transition zone between a trabecular meshwork and a corneal endothelium of the eye; a posterior portion configured to contact a peripheral iris of the eye; and a central portion connecting the anterior portion and the posterior portion of the body. A method for stabilizing the iredeocorneal angle of the anterior chamber using a stent is also disclosed herein.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/680,453 filed on Aug. 7, 2012, which is hereby incorporated byreference in its entirety

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates broadly to a structure for insertion in theanterior mammalian eye for treatment related to natural, predictableaging changes. More particularly the invention relates to a surgicallyimplanted device for the human eye. The device provides structuralsupport to specific ocular anatomy as a means to counteract changesnaturally brought about by aging.

2. Description of the Related Art

All human eyes go through physical changes as a result of the normalaging processes. These changes affect various structures of the eye. Thehuman eye has three chambers. The largest is the vitreous chamber. It isfilled with the gelatinous material of the vitreous body. This materialfills the eye and principally serves to maintain the shape of the eye.It also plays a role in accommodation to anchor the posterior lensattachments and interact with induced forces. In front of the vitreouschamber are the posterior and anterior chambers. These chambers alsoplay a role in maintaining the shape of the eye through the mechanism ofbalancing the production and drainage of aqueous humor. This fluid fillsboth chambers, which are separated by the iris. The pupil is the area ofcommunication between the two chambers. The aqueous humor is produced bythe ciliary body in the posterior chamber and then circulates forwardthrough the pupil to the anterior chamber. The fluid then slowly filtersthrough the annular structure of the trabecular meshwork and its distalsystem. The anterior chamber is demarked by the cornea and iris. Theboundaries of the posterior chamber are the iris and anterior lenscapsule. The posterior chamber peripherally reaches to the ciliary body,which is the location of the musculature and apparatus attachmentresponsible for accommodation.

Accommodation involves constriction and relaxation of the ciliarymuscles to achieve the control of focus. The process of accommodation isnaturally controlled by the brain. It is an automatic process thatresults in clear vision by manipulation of the lens shape and positionto focus light on the retina. The eye goes through a predictabledegradation of accommodation with aging. The focusing apparatus becomesprogressively more flaccid over time. The musculature and feedbackmechanism remain intact, but the ability to actuate change and focusdiminishes throughout life, until it is essentially totally ineffective.This process is known as presbyopia. The youthful eye has excessiveability to accommodate in the order of tenfold of what is generallyrequired. This surplus erodes over time, and usually reaches thethreshold of being initially problematic at 40 to 45 years old. Thedegradation continues to progress and usually renders the eye withcomplete inability to sustain any near focus by the age of 60. This is avery relevant juncture with respect to the aging process of the eye andsubsequent prevalence of various disease processes as they manifest.These predictable changes result in an anterior shifting of the lens andfocusing apparatus. The lens and apparatus are attached by microligaments known as zonules. The zonules become progressively moreflaccid with aging. The cause of this increased flaccidity is likely twofold. The zonules simply stretch over time due to perpetual use. Thisstretching is likely a contributing factor, but aging changes to theactual lens is responsible for the majority of change. These agingchanges eventually manifest as cataracts. Cataract development is apredictable and understood change to the aging eye. The matrix of thecrystalline lens becomes cloudy and impairs vision. This typicallybecomes problematic enough to require cataract surgery between the agesof 70 to 80. As part of the process the lens stiffens, thickens, andsubsequently increases in diameter. This increase in diameter results inoutward displacement of the zonule attachments. The entire focusingsystem becomes relatively slack and displaces forward. The thickening ofthe lens also compounds these forward forces as the vitreous body pushesthe structures from behind. Surgically removing the cataract becomesnecessary and is common practice.

At the stage prior to surgery, the intact aged eye has to maintainfunction with very unfavourable displaced and compressed anatomy. Theprevalence of various eye diseases begins to increase dramatically afterthe first five decades of life. These diseases include, but are notlimited to, glaucoma, Fuchs' corneal dystrophy, and retinal detachments.These three diseases are discussed herein, as each disease relates toforward shifting anatomical changes. Presbyopia and refractive error arealso discussed, but are not considered to be diseases.

Glaucoma is a disease which is diagnosed by evidence of vision loss ormeasured change to the optic nerve and the retinal nerve fiber layers.It is estimated that over 4 million Americans have glaucoma, but onlyhalf of the people who suffer from the disease are aware of theircondition. Approximately 120,000 people are blind as a result of thedisease. Glaucoma is the second leading cause of blindness in the world.Estimates put the total number of suspected cases of glaucoma at about70 million worldwide. Glaucoma is a group of diseases that relate tointraocular pressure (TOP) and the aqueous humor fluid dynamics of theeye. It is a balance between the rate of aqueous production from theciliary body in the posterior chamber and drainage via the trabecularmeshwork and its distal system located in the anterior chamber. It isestimated that the ciliary body produces aqueous at an average rate of2-3 micro liters per minute which translates into about 1.5 liters peryear. There are variations in rates of production; however, thesefluctuations are likely not as significant as the ability to drain thefluids, to balance pressure. The aging of the eye results in apredictable anterior shift of the structures posterior to the trabecularmeshwork. This shift results in restriction of flow based on thestructural change. Evidence of this shift is observed clinically when acataract is surgically removed. On average, there is a 17% decrease inintraocular pressure (TOP), shortly after surgery. The anterior chamberangle instantly widens upon removal of the lens. The structure of thetrabecular meshwork is able to open under these favourable changes. Thetrabecular meshwork is a mesh-like structure of tapering pores thatdirect the fluids into Schlemm's canal. The natural architecture of thisporous tissue cannot perform its function well under compression.Glaucoma patients often undergo cataract surgery prematurely to takeadvantage of the drop in baseline IOP. Cataract surgery could be delayedor avoided in many cases where the need for the operation is driven bythe pressure reduction aspects. The visual complications of naturalaging cataracts are generally noticed by one's early sixties. Visioncontinues to decline typically requiring cataract surgery at agesranging from early to mid seventies. The average life expectancy in theUnited States from birth is 78. It is more relevant to consider that theaverage life expectancy from an age of 63 is 20 years. Thus, asignificant portion of the population does not live long enough torequire cataract surgery based on vision needs.

Although glaucoma is a group of diseases, it can generally be classifiedinto two categories: closed angle and open angle glaucoma. Closed angleglaucoma is a medical emergency when the angle is truly closed. Thisoccurs when the peripheral iris occludes the trabecular meshwork.Topical and systemic pharmaceutical agents must be employed and often anemergency iridotomy is needed. An iridotomy involves makingpuncture-like openings through the iris without the removal of iristissue. It is performed either with standard surgical instruments or alaser. The iridotomy allows for instant equalization of IOP between theanterior and posterior chamber.

Primary Open Angle Glaucoma (POAG) accounts for the majority of glaucomacases. It presents with an apparently open drainage structure and oftennormal intraocular pressures. It is characterized by progressive opticneuropathy resulting in atrophy of the optic nerve and the nerve fiberlayers. The disease process must have factors that are not apparent uponsuperficial anatomical observation and clinical IOP measurements. It iswell documented that IOP fluctuates. Animal studies where IOP measuringprobes have been implanted have demonstrated very dramatic results.Rabbit and monkey subjects produced TOP spikes in the order of 90 mmHg.This represents pressure almost six times normal values. This highlightsthe necessity of IOP clearing time for these spikes to maintain eyehealth. The eye must be able to sustain brief spikes in IOP. Sneezingand rubbing one's eyes would be examples of normal acute IOP spikes.Early POAG cases are likely, in part, the inability of the eye'sdrainage system to facilitate a safe pressure clearing time. In theseopen angle cases the trabecular meshwork structure would be initiallycompressed internally and out of superficial view. This coincides withthe stage of rapid decline in loss of accommodation at the age of 50 to60. This directly correlates to the age where the incidence of glaucomadramatically increases. The angle is internally compressing in theperiphery as the ciliary body and its structures shift forward. Theangle and whole anterior chamber are narrowing. The farther forward thestructures shift, the greater the zonular flaccidity. As this progressesthere is less pulling on the anatomy adjacent to the trabecularmeshwork, which is known to decrease IOP. The action of pilocarpine eyedrops utilizes this mechanism to lower IOP. Pilocarpine also acts on theciliary muscle and causes it to contract. When the ciliary musclecontracts, it opens the trabecular meshwork through increased tension onthe scleral spur at the base of the trabecular meshwork. This narrowingtrend becomes more apparent 10 to 20 years later with significantcataract development. The central thickening of the lens producesadditional forward movement that is more evident on clinicalobservation.

In general the disease process is treated by isolated approaches tocertain aspects of the disease. Pharmaceutical agents represent theprimary form of treatment. They work on modulating production ordrainage of the aqueous fluids. These therapies are hindered by costs,compliance and side effects. Managing drug side effects in an elderlypopulation is difficult.

Tissue modifying procedures without device implantation havetraditionally been secondary or complimentary approaches to thepharmaceuticals. These surgical procedures include trabeculectomy andlaser trabuculoplasty. Trabeculectomy is very invasive surgery withconsiderable side effects. Scarring of the treated area is the greatestrisk for failure. Antimetabolite and antineoplastic medications areoften needed to augment the procedure. Other risks include infection,haemorrhaging, cataract formation, and hypotony. With hypotony, if thepressure remains too low for prolonged periods maculopathy and possiblevision loss my result. Laser trabuculoplasty is more widely utilizedbecause of its less invasive nature. Both procedures have very limitedsuccess and usually still require chronic paramedical use. Allprocedures which involve surgical trauma to compromised tissues mustcontend with the tissue's natural healing mechanism. The early positiveresponse often renders a compromised eye at greater risk for failure.There is a shift now to improved surgical procedures as a primarytreatment. An effective single procedure has the potential to reducecosts and eliminate compliance issues. Most devices available astreatments are focused on by-passing or bridging elements of thedrainage pathway. The development and improvement of glaucoma shunts orstents remains a very active field of investigation. The ultimate goalis to have a single surgical procedure as a first line treatment. Thereare various shunt designs that continue to evolve. The basic principleis to bypass the resistance of the trabecular meshwork and allow flow ofthe aqueous humor directly into the Schlemm's canal. If the shunt canremain clear, the pressure in the anterior chamber will remain equalizedwith the pressure in Schlemm's canal. From there on, the uveoscleraloutflow pathway remains intact to modulate IOP. The surgicalimplantation of such a small stent requires the extreme precision of askilled surgeon. It is also difficult to be confident that the stent haspenetrated the tissues as required to be effective. The lumen of thestent must remain open. The risk of scarring and blockage will always beof concern for patency.

All glaucoma treatments and variations of treatments have notabledisadvantages and limited success. Medication has significant sideeffects and surgery results in tissue trauma. In both cases, the cost oftreatment is high. The average direct cost of glaucoma treatment rangesfrom $623 per year for patients in the earliest stages and in excess of$2,500 a year for end stages of the disease. The annual total costs forglaucoma are approaching $3 billion in the U.S. economy alone.Procedural short term benefits can often result in additional costsassociated with failure and complications. A true treatment for glaucomais a common goal. The drainage systems of the eye may be best leftintact if it is possible to provide assistance to circumvent thedegenerative process. Trauma and scarring will inevitably compound theregenerative process. Implantation of a device to provide structuralsupport offers promise. It may be possible to cure glaucoma throughproactive prevention. Stem cell activity and cellular regeneration inthe trabecular meshwork also are likely involved. A device to stimulatethe responsible stem cells along with structural support could providethe eye with all that is necessary to prevent the manifestation ofglaucoma.

Fuchs' Corneal Dystrophy is a group of degenerative diseases of thecorneal endothelium. The endothelium is a monolayer of specialized,flattened, mitochondria-rich cells that line the internal surface of thecornea. Fuchs' dystrophy is clinically observed as an accumulation offocal outgrowths called guttae which are a thickening of the Descemet'smembrane. This results in corneal edema leading to decreased vision andpotentially vision loss. It is estimated that 5-10% of the populationover 50 years old have clinically significant manifestation of thedisease. The underlying cause is a deficiency of corneal endothelialcells. The density of endothelial cells on the posterior surface of thecorneal predictably decline with aging. There has been significantresearch and discovery in the genetics of Fuchs' variants. There areearly and late onset variations, and women tend to be more affected atan early stage. The common link to all is the decline in endothelialcell density. Evaluation of the endothelium by specular microscopy candemonstrate classic changes of Fuchs' endothelial dystrophy. With thebackground of the invention in mind, discussion will focus on thecorneal endothelium and its role. The principal physiological functionof the corneal endothelium is to allow nutrients from the aqueous humorto diffuse into the superficial layers of the cornea, while at the sametime actively pumping water out of the cornea back into the anteriorchamber. Thus, the corneal endothelium effectively keeps the cornea frombecoming edematous and losing clarity. Treatment options vary dependingon severity of symptoms and state of disease progression. Earlytreatments are targeted at reducing the edema. These treatments includetopical dehydrating agents, warm air to increase evaporation, loweringIOP, and topical nonsteroidal anti-inflammatory drugs. Treatment isnecessary until it is not possible to preserve good vision; at thatpoint keratoplasty is necessary. Penetrating keratoplasty (PK) has beenthe standard for treatment of Fuchs' endothelial dystrophy. PK involvesreplacement of the full corneal thickness with donor tissue, even thoughonly the endothelial layer is defective. In recent years, major advancesin this field have made replacement of only the endothelial layerpossible, without disturbing normal anterior structures of cornea usingendothelial keratoplasty. Both are effective procedures, but often havecomplications and limited duration of effectiveness. Approximately 10%of those identified with the dystrophy will need keratoplasty. Thepurpose of transplantation is to increase endothelial cell density andthus restore function. As a result, a procedure that allows the eye toregenerate its own endothelial cells may be an effective treatmentoption. Recently the stem cells responsible for this have been locatedin the posterior limbus. At this junction between the cornea and sclera,there is an area known as the transition zone where stem cells believedto be responsible for endothelial and trabecular meshwork cells reside.Schwalbe's Line demarks part of the transition zone. The stem cells havebeen observed to be stimulated after laser trabuculoplasty for glaucomatreatment. Stem cells are known to be activated by trauma. In thesecases, the stimulation can be beneficial or detrimental if overstimulated. Mechanical forces are also known to trigger stem celldifferentiation. The mechanical stimulation model may be verysignificant with respect to corneal endothelium regeneration. The linkto a decline in endothelial cell density and age may very well becorrelated to a decline in accommodative ability. By the age of 45,approximately half of our endothelial cells and most of the ability toaccommodate have been lost. A child has potentially ten times moreaccommodative ability than necessary. Such excessive power to focuswould translate into significant forces induced by the ciliary musclesand accommodative apparatus. The transition zone where the stem cellsare located absorbs some of these forces. It would be logical to expectcertain level of cellular activity to result. Implantation of a deviceto induce mechanical forces to the transition zone would have thepotential to stimulate stem cells. The device will need to provide anappropriate amount of stimulation by means of variable forces andcontact area with the transition zone. If a healthy population ofendothelial cells can be maintained, Fuchs' dystrophy should notmanifest. The underlying genetic predisposition will still exist, butinduced mechanical stimulation has the potential to prevent the diseasesymptoms from manifesting.

Retinal Detachments are generally categorized into idiopathic,traumatic, advanced diabetic, and inflammatory disorders. The majorityof disorders fall into the idiopathic classification. This grouping ofspontaneous retinal detachments dramatically increases after the age of40 and peaks at about the age of 60. The bulk of these idiopathicdetachments are vitreoretinal in origin. The vitreous humor changes inconsistency with aging. Its boundaries shrink away from the retina. Thisseparation is known as a posterior vitreous detachment (PVD). As thevitreous separates, it can pull the retina with it in areas of excessiveadhesion. The incidence of retinal tears resulting from a PVD varies onaverage between 5% and 15%, depending on the presentation. The processof the PVD can be asymptomatic or symptomatic with photopsia. Flashes orsparks of light in the absence of true light are indicative of tensionat retinal adhesions and present with greater risk. The symptoms usuallysubside once the process resolves. Floaters may remain after the processis complete. In the event that the adhesions does not release, a retinaldetachment is likely to occur. Retinal detachments of this etiology havea particularly strong correlation with the decline in accommodativeability. It is known that the ciliary body remains active even with lackof any sustainable accommodation. The feedback mechanisms to accommodatealso remains, but the cortical stimulation to accommodate is met with alack of response that ultimately can produce an over active muscularresponse of the accommodative apparatus. The vitreous body and thezonular attachments have a significant role in the apparatus. There isdebate over what is responsible for the ability to accommodate. Theexact combination of actions and reactions is not important for thediscussion of retinal detachment associated with PVD's. What issignificant is the balance of forces. When the ciliary body contracts itrelaxes the circumferential lenticular zonules. These include theequatorial, anterior, and posterior zonular limbs The area of tractionexists along the anterior hyaloid of the vitreous body. There arehyaloid zonules that anchor here and ultimately transfer forces toretinal adhesions. The dramatic increase in retinal detachment must havesome relation to the actions of the complex accommodative mechanism.When the eye has adequate accommodative control, there is a balancebetween ciliary contraction and relaxation. The accommodative mechanismwould predominately be in a relaxed state, when viewing beyond a fewfeet. Effectively this state puts tension on the lenticular zonulecomplex, pulling the lens back and relieving tension on the retinalattachments. The opposite is true of the response to near focus. Theciliary body contracts releasing tension on the lenticular zonuleattachments. The vitreous body and its gelatinous characteristics pushthe lens forward to accommodate. The forward movement is retained bytension transferred around the anterior hyaloid and retinal attachments.With presbyopia the concern is how the feedback mechanism responds to alack of focus. The action and reaction do not balance and causeinstability. The ciliary body easily can go into spasm under thesecircumstances. These spasms can clinically present as ocular pain. Theciliary muscle may very well become stronger as accommodative abilitydiminishes with aging. The retinal adhesion will be put undersignificant traction resulting in the inevitable PVD and risk of retinaldetachment. The relationship is complex and it is difficult to isolatethe components of the accommodative mechanism. Other tissue relatedchanges with aging must also be factors.

Retinal tears and detachments are treated by a variety of procedures.Success of treatment is high if the detachment is treated in a timelymanner. When tears are seen clinically there are generally twoapproaches, laser photocoagulation and cryopexy. Both methodsessentially scar the tissue around the tear to stabilize it. Retinaldetachments have more involved surgical treatments. Pneumatic retinopexyis the least invasive. The procedure involves injecting a gas bubble inthe eye to float the retinal back in place where it can reattach.Photocoagulation or cryopexy are then used to stabilize any holes ortears. Scleral buckling surgery is another surgical procedure. Thesurgeon places a piece of silicone sponge, rubber, or semi-hard plasticon the outer layer of the eye and sews it in place. This relievestraction on the retina, preventing tears from proceeding to detachments,by supporting the retina. The most invasive treatment is a vitrectomy.This procedure involves removal of the vitreous body from the eye.Vitrectomy gives the surgeon better access to the retina to repair holesand close large tears.

A procedure that could restore a functional amount of accommodationcould reduce retinal traction by stabilizing contraction of the ciliarymuscles. The feedback would be restored and the accommodative systemwould predominately be in a state that relieves tension on the vitreousbase and retina. To achieve this reduction in retinal traction, theanterior displacement of the whole system must be returned to a moreposterior position. This repositioning could be achieved through carefulcalculated sizing and implantation of a device to provide structuralsupport and targeted appositional forces.

Refractive Error Correction encompasses a variety of approaches toachieve clear vision. All eyes have a need for visual assistance byoptical or surgical procedures during a life time. Emmetropia is themost common presentation. This is a state of vision when one requires nooptical aids to see clearly when distant viewing. These individuals haveno need for correction until presbyopia sets in at mid life. This lossof accommodative ability is true of all eyes regardless of distancerefractive status. The non emmetropic eyes can be divided into myopia orhyperopia, respectively nearsighted or farsighted eyes. Astigmatism isgenerally present in variable amounts. This represents an unequalcurvature of the cornea or internal lens of the eye. There are infinitevariations in refractive error and many treatment options available. Themost common treatments include spectacles and contact lenses.Essentially all refractive errors can be treated by variations of thesesolutions. There are many other refractive modification proceduresavailable. Mostly these treatments are elective lifestyle procedures,but in some cases medically necessary. Cataract surgery is an example ofnecessary surgery. Cataract extraction is the most common surgicalprocedure in the United States. There are two types of cataract surgerycommonly employed today. Standard extracapsular cataract extractioninvolves removal of the lens in one piece along with the front portionof the lens capsule. This procedure is still utilized, but in limitedcircumstances due to the larger more invasive incision needed.Phacoemulsification small incision cataract surgery is essentially thestandard of care. The surgery utilizes ultra sound energy to fragmentthe lens so it can be evacuated through the small incision port. Thetechnique employs a foldable posterior chamber interocular lens (PCIOL)to facilitate transplantation through the small incision. The PCIOL ispositioned in the remaining lens capsule structure and centrallypositioned by flexible haptics. This small incision technique hasgenerally replaced other procedures. It is noted that there are a widevariety of PCIOL's available in various designs and materials. Surgeonshave significant surgical liberties in the cataract extraction field.Foldable anterior chamber interocular lenses (ACIOL) have recently beendeveloped. These lenses are employed by the same small incisiontechnique. They are placed in the anterior chamber and positioned byflexible haptics resting in the anterior chamber angle. ACIOL's aregenerally designed to be used in phakic eyes as they are positioned inthe chamber anterior to the lens. This is usually an elective procedureto correct high or difficult prescriptions. The procedure is resorted towhen other refractive devices or surgical options are not possible orhave limited potential.

The market for elective refractive surgery is well established.Refractive surgery without device implantation includes: RadialKeratotomy (RK), Astigmatic Keratotomy (AK), Photo-RefractiveKeratectomy (PRK) and Laser Assisted In-Situ Keratomileusis (LASIK). RKand AK involve carefully placed superficial incisions into the cornealstroma in a radial fashion. These procedures are not performed anymore,and are predecessors that led to PRK and LASIK. The utilization oflasers with PRK and LASIK has much greater control and predictableoutcomes. Modern PRK and LASIK are considered elective procedures. Theycan correct most naturally occurring refractive errors. These are nottruly reversible techniques because tissue is removed with the laser.

The implantation of interocular lenses accounts for nearly all of thedevices implanted to correct refractive errors. The laser surgerytechniques dominate the tissue altering procedures by re-shaping thecornea. Intra-stromal corneal rings are an alternative option for lowlevels of myopia and astigmatism. Small incisions in the corneal stromaare made. Two crescents or semi-circular shaped ring segments areimplanted on opposing sides away from the central cornea. The embeddingof the rings in the cornea has the effect of flattening the cornea andchanging the refraction. Intacs are the FDA approved device for thisprocedure. They are made of a relatively rigid material,Poly(methylmethacrylate) (PMMA). Intacs have not gained significantmarket share despite being marketed as a reversible procedure. Presentlythey are often used for the treatment of Keratoconus. Their semi-rigidstructure offers support to a structurally failing cornea. There isextensive data from photorefractive surgery and cornea curvaturealtering proceeds. The cornea has an average refractive power of 45diopters. This high power along with 18 diopters from the natural lensis required to focus light to produce images at the 24 mm axial lengthof the eye. The majority of naturally occurring refractive errors arewithin a prescription of one diopter. This is a very small amount withrespect to the total power of the system. A device with the ability tointernally expand along the corneal base would flatten corneal curvatureresulting in decreased myopia. The cornea only requires a flattening of75 microns to achieve a one diopter decrease in myopia. Achieving such aflattening of the cornea would only require an increase in diameter of60 microns at the corneal base.

The loss of accommodative ability remains one of great interest withinthe field of refractive correction. The ability to change focus providesthe optical system control and an advantage over any static approach.The development of a device to rejuvenate the natural ineffective agedsystem is being actively perused. The advantages of such a system couldbe more significant than the visual control and clarity. Stability ofthe accommodative musculature has the ability to relieve the retinaltension by returning the system to equilibrium. Present techniques andprocedures under investigation to restore accommodation are eitherexternal or internal to the posterior chamber. Externally there aretechniques that suggest the suturing of bands around the eye to increasethe diameter and provide a more rigid external base for the ciliarymuscles internally. The concept is to reduce flaccidity of the zonularcomplex by external expansion to enable some reaction to theaccommodative actions of the ciliary muscles.

However, the eye is dynamic and changes in refractive status do havepredictable patterns as well changes that cannot be anticipated. Intheory, the eye cannot be static until it is aphakic after cataractsurgery. At this stage there is no effective accommodation. The corticalconnections and accommodative musculature still remain, but no lensremains to facilitate a response. Developing a way of utilizing thecortical and muscular system to facilitate accommodation will be ofgreat benefit. An artificial lens is required to achieve this. FocusingPCIOL's are in development and are already available. The lens isimplanted in the posterior chamber replacing the natural lens. Theconcept is to have a lens with shape changing characteristics to harnessthe movement of the ciliary muscle during accommodative stimulation.These lenses will continue to develop, but presently have limitedsuccess. Harnessing accommodative forces in the anterior chamber wouldallow for the development of a shape changing lens implant in front ofthe iris.

SUMMARY OF THE INVENTION

A stent device implanted into the anterior chamber angle could providevarious structural elements and forces to restore some accommodativeability in the phakic eye. The stent must have precise anatomicalplacement to achieve this. The positioning of the stent is essentiallyalong the internal foundation of the cornea. In this position it caninduce forces radiating outward and anteriorly along the posteriorcornea base. The forces would translate to a re-positioning of theaccommodative apparatus to a more posterior placement. In this positionthe eye can restore some level of accommodation. The forces applied atthe corneal base can also be adjusted to manipulate corneal curvatureand change refractive error.

In addition, the stent device implanted at the internal base of thecornea could translate motion if it can articulate. Embodiments of sucha device would provide a base to implant the novel concept of a focusingACIOL. The stent device, along with the additional here in claimedinvention of the complimentary focusing ACIOL, has the potential toprovide pseudo-accommodation. This configuration of an accommodatingACIOL will be discussed in relation to the stent device but should notbe limited to the preferred embodiments to be discussed and illustrated.The concept of an accommodating ACIOL is dependent on the specificanatomical fitting of the stent device and as such is considered anextension of this invention. The stent of the present invention isconfigured to provide such features.

Therefore, generally provided is a surgically-implantable device for thehuman (or mammalian) eye that addresses or overcomes some or all of thedeficiencies and drawbacks in the field of medical eye care. Preferably,provided is a surgically-implantable device for the human (or mammalian)eye that facilitates the restoration of the architecture of the anteriorchamber angle and underlying accommodative apparatus. Preferably,provided is a surgically-implantable device for the human (or mammalian)eye that provides the eye with ability to restore, regenerate andrejuvenate various elements of normal function. Preferably, provided isa surgically-implantable device for the human (or mammalian) eye thataddresses the clinical need for a faster, safer and more cost effectivemethod to treat diseases and degenerative conditions of the eye.

The anatomical area of implantation is very specific, but within theanatomy there will be various embodiments of devices. The description ofpreferred embodiments of this invention is not limited to variations indesign, materials, manufacturing and procedures relating to implantationof the invention. Any embodiment of this device will involve minimallyinvasive small incision by clear cornea, modified clear cornea orscleral tunnel implantation techniques. Preferred embodiments of thisdevice would be removable and thus enable reversal of failed procedures.

The device may be specifically fit according to the involved anatomy andpatient specific sizing with respect to this anatomy. Recent refinementsand advances in imaging technology are now allowing for very accurateclinically available equipment. The introduction of time domain anteriorsegment optical coherence tomography (AS-OCT) technology allows for invivo, cross-sectional tissue imaging. This provides diagnostic andmanagement capabilities that is far superior then before. Prior to theintroduction of this technology in 2006, the only way to obtaincross-sectional images of the anterior segment was with histologicalsectioning The importance of this technology is apparent when applyingthe specific anatomical placement of the potential embodiments of thedevice.

In a preferred and non-limiting embodiment, an ocular stent forinsertion in an anterior chamber of an eye includes an annular body. Thebody includes: an anterior portion configured to contact a surface of atransition zone between a trabecular meshwork and a corneal endotheliumof the eye; a posterior portion configured to contact a peripheral irisof the eye; and a central portion connecting the anterior portion andthe posterior portion of the body.

In certain embodiments, the anterior limits of the device may encroachon and make contact with the adjacent trabecular meshwork and cornealendothelium. The posterior portion of the device will be configured tobe in contact with a portion of the surface of the peripheral iris. Theperipheral limits of the posterior contact may extend around theanterior chamber irideocorneal angle to cross the anterior chamberexposure of the ciliary body up to or beyond the scleral spur toencroach on the trabecular meshwork. The central range of the posteriorcontact along the iris will be sufficient to support the range of theciliary body structure posterior to the iris. The anterior andperipheral portions of the device will have structural connection withconfiguration to maintain the device out of contact with the majority(or other proportion) of the surface of the trabecular meshwork.

Additionally, certain embodiments of this invention have a grouping ofobjectives that are inherent to the action of mechanically restoringanatomical architecture of the aging eye. Implantation of the devicewill inevitably have multiple actions regardless of the desired action.By design, the device cannot single out any one objective withoutincluding the other complimentary objectives. As such the device can beseen to have the primary objective of reversing the natural agingprocesses with respect to certain aspects of the eye.

In accordance with a further preferred and non-limiting embodiment, anocular stent for insertion in an anterior chamber of an eye is provided.The stent includes: at least one annular cord; a plurality of anteriorarms extending from the cord in a first direction; and a plurality ofposterior arms extending from the cord in a second direction, the seconddirection being different than the first direction. The stent isconfigured to be receivable within an irideocorneal angle of theanterior chamber of the eye. Additionally, the anterior arms and theposterior arms together are configured to form an articulating joint.

The above-describe exemplary embodiments of the invention are providedfor treatment of eye conditions related to aging. One aspect of theinvention relates to a medical device system for treating the tissues ofthe trabecular meshwork. The trabecular meshwork and thejuxtacanilicular tissue collectively are responsible for the resistanceto the out flow of the aqueous humor. The trabecular meshwork is thus alogical target for tissue rejuvenation and stimulation for the treatmentof glaucoma. The various possible embodiments of the device all applyappositional forces anterior and posterior to the trabecular meshwork.Preferred embodiments may have partial contact with the trabecularmeshwork. Significant contact with the anterior portion of thetrabecular meshwork may produce increased stem cell activity. As such,centering the anterior portion of the device at an anterior portion ofthe trabecular network may provide improved results. Despite anycontact, the device will effectively span and open the structure toenhance flow of the aqueous. Since there is no true treatment, controlof the disease is the goal. Lowering IOP by 20% relative topre-treatment levels is a general rule to measure initial success.

Another aspect of the invention relates to stem cell activation byappositional stimulation to the posterior limbus transition zone. Thereis evidence of stem cells for the corneal endothelium as well as stemcells for the trabecular meshwork residing there. Successful stimulationhas regenerative potential for Fuchs' corneal dystrophy and glaucomarespectively. Regeneration of trabecular meshwork tissues would be verycomplimentary to the aforementioned structural aspect of the device toincrease outflow. Stimulation of the endothelial stem cells offerspromise as a potential treatment or prophylactic measure to circumventnormal endothelial cellular loss with aging. Mechanical stimulation ofstem cells is well known in various tissues of the body. Regularphysical stimulation of tissues is often needed to maintain theregenerative processes. The internal limbal transition zone of thecornea does not have the same mechanical stimulation as the externallimbal area responsible for epithelial regeneration. There is continualdirect mechanical interaction with external eye and perpetualregeneration is required to sustain healthy tissues of the external eye.The internal transition zone must have internal mechanical stimulationby translation of accommodative energy. A child's excessiveaccommodative ability can translate into forces greater than ten timesthat of the middle aged adult. Embodiments of this device will have theability to produce variable amounts of appositional forces on thetransition zone. Although different in presentation than accommodativeforces, it is hypothesized that such appositional force will result infavorable stem cell activity. Such activity can be easily measured as itrelates to endothelial cell density. Evaluation of the endothelium byspecular microscopy is a non-invasive way to achieve this.

Some other aspects of the invention relate to repositioning andstabilization of the accommodative apparatus. The posterior contact ofthe various embodiments is essential to the overall function of theinvention. The anatomical placement of this contact is such to transferan adequate amount of force through the iris base to result in aposterior repositioning of the ciliary body. This repositioning of theaccommodative apparatus will be restorative to some accommodativefunction. The ability to restore focusing ability is a very desirableaspect of the device embodiments. Calculations and adjustments will bepatient specific to achieve the desired results. Loss of accommodationis not classified as a disease, but rather considered an inconvenientresult of aging. It is a degenerative condition that does relate to themanifestation of disease processes. Implantation of an embodiment ofthis device for the purposes of restoring accommodation or changingrefractive status will also have benefit(s) of the additional aspects ofthe device.

Another attribute of the device relating to repositioning of theaccommodative apparatus is retinal stabilization. The physical posteriorshifting of the ciliary body will relieve excessive tension translatedto retinal attachments linked to the accommodative apparatus. Restoringaccommodative control is also a significant part of reducing retinaldetachment. Accommodative control will allow for stable control of theciliary muscle and reduce or prevent ineffective unnecessarycontractions. The various embodiments will be able to be sized toachieve the desired effect and reduce the risks associated with retinaldetachments of this etiology.

Embodiments of the invention can be designed to position an AIOL. Thespecially designed lens can be retained in the base structure of theinvention. The implantation of such a lens would be indicated withcataract extraction, but variation could be employed with a phakic eyeas well. The circumferential designs of the invention, in itsarticulating foams, will allow for the opportunity to develop a lenscapable of changing its radius of curvature and position in relation tonatural accommodative stimulation and muscular response. The ciliarybody muscle induces forces during accommodation that can allow thearticulating embodiment to induce small amounts of movement. Themovement would radiate inward upon contraction of the ciliary body withaccommodative stimulation. Accommodative feedback and ciliary muscleaction are still active even in the aphakic eye. There is no responsewithout the natural lens, or a PCIOL that is static. Implantation of alens that can tie into the feedback mechanisms would return the controlof focus. There is very significant prior art with respect toimplantable lenses. This design concept to work with embodiments of theinvention is a new concept that can utilize acrylic and silicon-basedmaterials. The design of this lens must have sufficient ability tochange curvature with small amounts of movement allowing a functionalaccommodative range. It will require a PCIOL of opposing power tocomplete the optical system. Calculations based on pairing of lenses canproduce accommodative responses in excess of that required under normalvisual demands. Preferred embodiments of this complimentary device areto be considered an extension of the original invention, and not to belimited in design, materials or manufacturing process.

A variety of biocompatible materials can be employed to manufacture theembodiments of the device and components of this invention. The devicemay utilize such a variety of materials, many of which have ongoingproven bio-compatibility in excess of 25 years. All embodiments of thedevice(s) are to be removable and replaceable. The device(s) will bevisible by mean of non-invasive visual and imaging assessment. Thefollowing materials are examples but not to be considered limiting forthe design and manufacturing of the device(s) and possible components ofthe invention. There are a variety of proven biocompatible materialsused in various ocular implants. The original interocular lenses weremade from Polymethylmethacrylate (PMMA) and were not foldable.Presently, the most common ocular implants are the posterior chamberinterocular lens (PCIOL). These are primarily made of silicone oracrylic and often have PMMA components. The material of choice forsingle piece embodiments must be bio-compatible, semi rigid, foldableand have a constant memory of shape. A clear material would becosmetically favorable since the ring will be partially visible. It mayalso be possible to color match or enhance the iris color. There issignificant debate over whether hydrophilic or hydrophobic materials orsurface treatments are superior. Some proven PCIOL's utilize bothproperties. Potential materials may include: Hydrophobic Acrylic,Hydrophilic Acrylic, Acrylic Polymer, Silicone,Poly(styrene-block-isobutylene-block-styrene) SIBS, Silicon Elastomer(Biosil), and Heparin Surface Modified Acrylics. The annular design ofthe device can allow for very soft and pliable materials to inducesufficient forces. The involved soft tissues will require delicate andcontrolled contact. The multi-piece embodiments can utilize a widerrange of materials since the individual components do not require thesame flexibility as those to be utilized in the single-pieceembodiments. A proven material, such as PMMA, can be utilized. It hasrigid properties, is extrudable and stable for laser cutting or latheturning. Other methods of manufacture can include: molding techniques,vacuum forming, and solvent casting. Particular methods of manufacturehave not been disclosed. It is understood that a variety ofmanufacturing methods do exist with substantial prior art in the fieldof ocular implants. One or multiple methods of manufacture may beemployed in the manufacture of single or multiple components of thepossible embodiments of this invention. It may also be useful to coatcomponents of this device to enhance its functional properties orbiocompatibility. It may also be useful to coat the device withtherapeutic agents or implant a complimentary device containingtherapeutic agents.

According to a further aspect of the invention, a method of stabilizingthe irideocorneal angle of an anterior chamber of an eye demarked by thecornea and iris is provided. The method includes the step of inserting astent into the anterior chamber, such that the stent is in contact withsoft tissue of the anterior chamber. Following insertion of the stent,pressure is applied, simultaneously, in an anterior direction to asurface of a transition zone between an anterior limit of a trabecularmeshwork and a posterior limit of a corneal endothelium of the eye withan anterior portion of the stent, and in a posterior direction to asurface of the peripheral iris of the eye with a posterior portion ofthe stent.

More particularly, implantation of the various possible embodiments ofthe device would be in accordance to the prior art of cataract surgeryrelating specifically to the implantation of foldable interocularlenses. The present state of lens implantation is highly developed, andthose skilled in the art have a variety of choices as to theirpreferences in materials and tools. Virtually all implanted ocularlenses are foldable, allowing for small, minimally-invasive, suturelessincisions. Smaller incisions that allow quicker recovery, better woundstrength and increased surgical control, result in lower complicationrates and better outcomes. Diamond spade knives are used to make a 2-3mm incision through peripheral cornea or scleral tunnel techniques. Theinterocular lenses are pushed through the small incision with a varietyof injector devices that usually consist of a cartridge that preparesthe lens by folding it and a plunger system to inject it. Those skilledin the art can utilize these established devices for purposes ofimplanting embodiments and components of the device. Although new toolsmay not be needed for purposes of implantation of the device(s), it willbecome apparent to those skilled in the art which available devices arebest suited as techniques evolve. Refinements of the tools andtechniques may lead to development of specific new tools forimplantation, manipulation and removal of the various stent devices.

The embodiments of this medical device and methods are provided inaccordance of the objectives to rejuvenate or restore elements of theeye. The disease processes and physiologic changes herein mentionedabove are as such detrimental to function. For purposes of summarizingthe invention, certain aspects, features and advantages of the inventionhave been described. It is herein to be understood that not alladvantages of this invention may be achieved in relation to anyparticular embodiment of the device(s) or adjunctive components of thedevice(s). As such, the invention may be embodied in configurations tooptimize one or various advantages. Implantation of the device may beindicated for any one advantage or combination of advantages asindicated for treatment or prophylactic intervention.

These and other features and characteristics of the present invention,as well as the methods of operation and functions of the relatedelements of structures and the combination of parts and economies ofmanufacture, will become more apparent upon consideration of thefollowing description and the appended claims with reference to theaccompanying drawings, all of which form a part of this specification,wherein like reference numerals designate corresponding parts in thevarious figures. It is to be expressly understood, however, that thedrawings are for the purpose of illustration and description only andare not intended as a definition of the limits of the invention. As usedin the specification and the claims, the singular form of “a”, “an”, and“the” include plural referents unless the context clearly dictatesotherwise.

Additional aspects and advantages of the invention will become readilyapparent to those skilled in the art upon reference to the providedfigures and detailed description of the preferred embodiments. Theinvention is not limited to any particular preferred embodiment(s)disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

Some of the advantages and features of the preferred embodiments of theinvention have been summarized herein above. These embodiments alongwith other potential embodiments of the device will become apparent tothose skilled in the art when referencing the following drawings inconjunction with the detailed descriptions as they relate to thefigures.

FIG. 1 is a schematic sectional view of an eye showing anatomical detailalong with in situ placement of a stent, in accordance with an aspect ofthe present invention;

FIG. 2 is a close up sectional view of FIG. 1 taken along section 2-2,providing more anatomical detail of the superior anterior segment of theeye relating to the stent, in accordance with an aspect of the presentinvention;

FIG. 3 is a schematic sectional view of an eye showing anatomical detailalong with in situ placement of a stent, in accordance with an aspect ofthe present invention;

FIG. 3A is a schematic sectional view of the eye and stent of FIG. 3taken along section 3-3, in accordance with an aspect of the presentinvention;

FIG. 4A is a schematic illustration of a divided front view of a stentillustrating continuous and/or divided variations of a ring, inaccordance with an aspect of the present invention;

FIG. 4B is a cross-section view of the stent of FIG. 4A taken alongsection 4B-4B, in accordance with an aspect of the present invention;

FIG. 4C is a partial side profile view of the stent of FIG. 4A takenalong section 4C-4C and having drainage ports, in accordance with anaspect of the present invention;

FIG. 4D is a cross-section view of the stent of FIG. 4A taken alongsection 4D-4D, in accordance with an aspect of the present invention;

FIG. 4E is a partial side profile view of the stent of FIG. 4A takenalong section 4E-4E and illustrating a beaded anterior surface, inaccordance with an aspect of the present invention;

FIG. 5 is a schematic sectional view of an eye showing anatomical detailalong with in situ placement of a stent, in accordance with an aspect ofthe present invention;

FIG. 5A is a schematic sectional detail of the eye and stent of FIG. 5taken along section 5-5 in accordance with an aspect of the presentinvention;

FIG. 6A is a schematic front view of a stent illustrating a single piecenon-continuous ring with a continuous tensioning O-ring in place, inaccordance with an aspect of the invention;

FIG. 6B is a cross-section view of the stent of FIG. 6A taken alongsection 6B-6B, according to an aspect of the present invention;

FIG. 6C is a partial side profile view of the stent of FIG. 6A takenalong section 6C-6C, in accordance with an aspect of the presentinvention;

FIG. 7 is a schematic sectional view of an eye showing anatomical detailalong with in situ placement of a stent, in accordance with an aspect ofthe present invention;

FIG. 7A is a sectional detail of the eye and stent of FIG. 7 taken alongsection 7-7 in accordance with an aspect of the present invention;

FIG. 8A is a half section front view of the stent of FIG. 7 as amulti-piece continuously joined ring with a continuous tensioning O-ringin place, in accordance with an aspect of the invention;

FIG. 8B is a cross-section view of the stent of FIG. 8A taken alongsection 8B-8B with illustrated anatomical detail shown, in accordancewith an aspect of the invention;

FIG. 8C is a partial side profile view of the stent of FIG. 8A takenalong section 8C-8C with anatomical detail shown as it would be seen inthe irideocorneal angle by means of gonioscopy, in accordance with anaspect of the invention;

FIG. 8D is a schematic drawing that illustrates details of thearticulating components of the stent of FIG. 8A, in accordance with anaspect of the present invention;

FIG. 9A is a schematic section view of an aphakic eye illustrating thestent of FIG. 7 in situ with an accommodating anterior chamberinterocular lens (ACIOL) and an adjunctive stationary posterior chamberinterocular lens (PCIOL), in accordance with an aspect of the invention;

FIG. 9B is a schematic drawing of a quartered front view of an eyeillustrating the various details of the stent of FIG. 7 and ocularanatomy, in accordance with an aspect of the invention;

FIG. 10A is a schematic drawing of a folding interocular lens injector,which can be utilized for implantation of a stent, in accordance with anaspect of the invention; and

FIG. 10B is a schematic drawing of a front view of an implantationprocedure, using the injector of FIG. 10A to inject a stent, inaccordance with an aspect of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The illustrations generally show preferred embodiments of the devicesused to treat predictable structural ocular aging changes of theanterior segment of the human eye. While the descriptions presentvarious embodiments of the device(s), it should not be interpreted inany way as limiting the invention. Furthermore, modifications, conceptsand applications of the inventions embodiments are to be interpreted bythose skilled in the art as being encompassed, but not limited to theillustrations and descriptions herein.

The following description is provided to enable those skilled in the artto make and use the described embodiments contemplated for carrying outthe invention. Various modifications, equivalents, variations, andalternatives, however, will remain readily apparent to those skilled inthe art. Any and all such modifications, variations, equivalents, andalternatives are intended to fall within the spirit and scope of thepresent invention. Further, for purposes of the description hereinafter,the terms “end”, “upper”, “lower”, “right”, “left”, “vertical”,“horizontal”, “top”, “bottom”, “lateral”, “longitudinal” and derivativesthereof shall relate to the invention as it is oriented in the drawingfigures. However, it is to be understood that the invention may assumevarious alternative variations and step sequences, except whereexpressly specified to the contrary. It is also to be understood thatthe specific devices and processes illustrated in the attached drawings,and described in the following specification, are simply exemplaryembodiments of the invention. Hence, specific dimensions and otherphysical characteristics related to the embodiments disclosed herein arenot to be considered as limiting. For the purpose of facilitatingunderstanding of the invention, the accompanying drawings anddescription illustrate preferred embodiments thereof, from which theinvention, various embodiments of its structures, construction andmethod of operation, and many advantages may be understood andappreciated.

A sectional view of an eye is illustrated in FIG. 1. The ocular stent 18in this anatomical placement represents certain preferred andnon-limiting embodiments. It is positioned in the anterior chamber ofthe eye. This chamber is bound by the cornea 32 anteriorly and the iris29 posteriorly. Aqueous humor 31 fills and circulates through thischamber. The cornea 32 is a clear collagenous tissue responsible formost of the focusing ability of the eye. It transitions into the whitecollagenous tissue of the sclera 23 along the limbus 33. The lens 30 issuspended by the zonular complex 28. The zonules 28 are ligamentoushaving their muscular attachments to the ciliary body 27 and opposingattachment into the equatorial region of the lens 30. The ciliary body27 is the muscular component of the accommodative complex. Along withthe ciliary body 27 and iris 29, the choroid 24 forms the uveal tract.The choroid 24 is the highly vascular layer which underlies the retina20. The retina 20 is centrally bound by the vitreous body, which isfilled with vitreous humor 25. This central body makes up the bulk ofthe volume of the eye. It maintains the eye's shape and plays a role inaccommodation. The central visual axis intersects the retina 20 at thefovea 22 of the macular region. This region is the most visuallysensitive and innervated area of the retina 20. All innervations andvascularisation of the eye is connected to the brain via the optic nerve21.

In FIG. 2, the anterior segment of the eye is shown with additionalanatomical detail around a preferred and non-limiting embodiment of theocular stent 18. The drainage structure of the trabecular meshwork 17and Schlemm's canal 19 are illustrated. The corneal endothelium 16 isillustrated as are the anterior 34 and posterior 35 lens capsules. Thezonular attachments to the lens 30 and ciliary body 27 are divided intothe anterior zonules 36, equatorial zonules 37, posterior zonules 38 andhyaloid zonules 39. The anterior hyaloid vitreous membrane 40 is theanterior boundary of the vitreous humor 25.

FIG. 3 is a detailed illustration of a preferred and non-limitingembodiment the ocular stent 18 in relation to adjacent anatomy. Theocular stent 18 is implanted in the peripheral irideocorneal angle 44 ofthe anterior chamber, having an anterior portion configured to becentered on and in contact with the surface of the transition zone 42between the anterior limits of the trabecular meshwork 17 and posteriorlimits of the corneal endothelium 16 or posterior aspect of the limbus41. The anterior limits of the ocular stent 18 may encroach on and makecontact with the adjacent trabecular meshwork 17 and corneal endothelium16. The posterior portion of the ocular stent 18 will be configured tobe in contact with a portion of the surface of the peripheral iris 29.The peripheral limits of the posterior contact may extend around theanterior chamber irideocorneal angle 44 to cross the anterior chamberexposure of the ciliary body 27 up to or beyond the scleral spur 43 toencroach on the trabecular meshwork 17. The central range of theposterior contact along the iris 29 will be sufficient to effectivelysupport the ciliary body 27 structure posterior to the iris 29. Theocular stent 18 may be formed with a boomerang shaped radial crosssection. In that case, the anterior portion and the posterior portion ofthe ocular stent meet at a central portion 12. As will be appreciated bythose having skill in the art, the central portion 12 may be integrallyformed with the anterior and posterior portions of the body.Alternatively, the central portion 12 may be a joint, such as anarticulating joint.

As will be appreciated by one having ordinary skill in the art, thestent 18 may be able to reposition and retain the position of theciliary body 27. For example, in the embodiment depicted in FIG. 3, theocular stent 18 is positioned in the anatomy of the eye to enablefavourable function. The ocular stent 18 spans the filtering structureof the trabecular meshwork 17 expanding and opening its porousstructure. This structurally supported configuration of the drainageanatomy will decrease IOP and promote rejuvenation of the tissues. Incertain embodiments, the ocular stent 18 is composed of a biocompatiblematerial that has structurally stable properties. The integrity of theanatomical organization will remain since the properties of the ocularstent 18 are required to be stable. These stable properties also willallow for consistent and accurate contact with the transition zone 42.This is required to induce appropriate forces at this area of stem cellactivity. The appositional stimulation of stem cells here can impactregeneration of corneal endothelial cells 16 and cells pertaining to thetrabecular meshwork 17. The posterior aspect of the ocular stent 18 isconfigured to assist in positioning of the trabecular meshwork 17 andtransition zone 42. This posterior contact along the iris 29 basetranslates forces required to reposition the ciliary body 27 andvariable forces from muscular action in the ciliary body 27 to thetransition zone 42. The posterior repositioning shifts the accommodativestructure posteriorly which in turn requires the structures to expandcircumferentially. This expansion will translate into a tightening ofthe posterior 38, equatorial 37, and anterior 36 zonules. The return oftension to these zonules will result in some degree of accommodativefunction. The return of function will stabilize muscular action by meansof effective feedback and control of the ciliary body 27. This isimportant as it relates to the hyaloid zonules 39. The posteriormovement of the ciliary body 27 will relieve excessive tension on thehyaloid zonules 39. This combined with returned control of theaccommodative musculature will relieve excessive tension beingtransferred to the hyaloid retinal connections and thus reduce the riskof retinal detachment. The stent 18 requires very specific sizing andanatomical placement. It will be possible to adjust the sizing to induceforces to enable some manipulation of refractive error. Morespecifically, the ocular stent 18 is positioned at the base of thecornea 32. This area of circumferential placement is the foundation ofthe cornea and as such the structural base of the cornea 32.

A divided front view of a preferred and non-limiting embodiment of theocular stent 18 is shown in FIGS. 4A-4E, for purposes of illustratingvarious embodiments of the stent 18. FIG. 4A illustrates a half sectionof a continuous variation of the ocular stent 18 having a communicationstructure, such as ports 14. As used herein, a “communication structure”refers to a structure such as a port, tube, opening, or through holeextending through the body of the stent 18 for permitting fluid to passtherethrough. The ports 14 equalize fluid pressures across the ocularstent 18. Six ports 14 are illustrated to convey the concept. The sizeand number of ports 14 can be varied to achieve a desired result. Asingle port 14 could be adequate to provide sufficient flow, butcontinued patency would be a concern so multiple ports 14 may beutilized. The ports 14 have the potential to reduce or virtuallyeliminate pigment dispersion into the trabecular meshwork 17. A superiorplacement of the ports 14 reduces pigment transfer allowing free pigmentto settle inferiorly blocked by the ocular stent 18 from passing intothe drainage structures. FIG. 4A illustrates a half section of anon-continuous variation of the ocular stent 18 having a beaded ortextured anterior surface 15. The ocular stent can be segmented ineither variation but is only illustrated in FIG. 4A. Having a smallsegment removed creates an internal snap ring design. This variation indesign would allow for greater variability in fitting the ocular stent18. The tensile modulus of the ocular stent 18 would allow for somevariability in diameter and induced forces from a particular size. Theremoved segment will also provide direct access to the structures of theanterior chamber angle. It would be possible to implant a stent thatpenetrates the trabecular meshwork 17 to provide direct flow of theaqueous humor 31 to Schlemm's canal 19. The non-segmented variationwould have virtually no variability and require precise sizing. Thebeaded or textured anterior surface 15 provides variable contact alongthe contact surface, allowing for equalization of fluid pressure acrossthe ocular stent 18. This would be required in the case of a continuousring design. The beading texture 15 also servers the purpose ofproviding a non-continuous surface in contact with the transition zone42. Variations in the texture can be manipulated to achieve optimizationof the appositional stem cell stimulation.

FIG. 4B is a sectional view of ocular stent 18 with the sectional viewof a port indicated by the dashed lines. FIG. 4C is a partial sideprofile view of the ocular stent 18 as it would be viewed from insidethe anterior chamber of the eye with the port openings visible. Theillustrated view orientating is indicated in FIG. 4A. FIG. 4D is asectional view of ocular stent 18 with the beading contour indicated.FIG. 4E is a partial side profile view of the ocular stent 18 as itwould be viewed from inside the anterior chamber of the eye with theanterior beaded surface visible. The illustrated view orientating isindicated in FIG. 4A.

With reference to FIG. 5, a preferred and non-limiting embodiment of anocular stent 47 is depicted. The ocular stent 47 is implanted in theperipheral irideocorneal angle 44 of the anterior chamber. The ocularstent 47 has an anterior portion configured to be centered on and incontact with the surface of the transition zone 42 between the anteriorlimits of the trabecular meshwork 17 and posterior limits of the cornealendothelium 16 or posterior aspect of the limbus 41. The anterior limitsof the ocular stent 47 may encroach on and make contact with theadjacent trabecular meshwork 17 and corneal endothelium 16. Theposterior portion of the ocular stent will be configured to be incontact with a portion of the surface of the peripheral iris 29. Theperipheral limits of the posterior contact may extend around theanterior chamber irideocorneal angle 44 to contact the anterior chamberexposure of the ciliary body 27 up to or beyond the scleral spur 43 toencroach on the trabecular meshwork 17. The central range of theposterior contact along the iris 29 will be sufficient to effectivelysupport the ciliary body 27 structure posterior to the iris 29. As inpreviously described embodiments, the stent 47 is configured toreposition and retain the position of the ciliary body 27. The ocularstent 47 spans the filtering structure of the trabecular meshwork 17expanding and opening its porous structure. This structurally supportedconfiguration of the drainage anatomy will decrease TOP and promoterejuvenation of the tissues. In certain embodiments, the ocular stent 47is composed of biocompatible materials that are relatively soft andflexible. The ocular stent 47 is designed to incorporate an O-ring 48 toprovide the structure with stability and ability to alter induced forceswith respect to the anatomical arrangement of the involved structures.These stable properties also will allow for consistent and accuratecontact with the transition zone 42. This is required to induceappropriate forces at this area of stem cell activity. The appositionalstimulation of stem cells here can impact regeneration of cornealendothelial cells 16 and cells pertaining to the trabecular meshwork 17.The posterior aspect of the ocular stent 47 is essential to theaforementioned actions on the trabecular meshwork 17 and transition zone42. This posterior contact along the iris base 29 translates forcesrequired to reposition the ciliary body 27 and variable forces frommuscular action in the ciliary body 27 to the transition zone 42. Theposterior repositioning shifts the accommodative structure posteriorlywhich in turn requires the structures to expand circumferentially. Thisexpansion will translate into a tightening of the posterior 38,equatorial 37 and anterior 36 zonules. The return of tension to thesezonules will result in some degree of accommodative function. The returnof function will stabilize muscular action by means of effectivefeedback and control of the ciliary body 27. This is important as itrelates to the hyaloid zonules 39. The posterior movement of the ciliarybody 27 will relieve excessive tension on the hyaloid zonules 39. Thiscombined with returned control of the accommodative musculature willrelieve excessive tension being transferred to the hyaloid retinalconnections and thus reduce the risk of retinal detachment. In apreferred and non-limiting embodiment, the ocular stent 47 requiresspecific sizing and anatomical placement, but has significant adjustmentdue to the O-ring 48 component. It will be possible to adjust the sizingto induce forces to enable some manipulation of refractive error. Theocular stent 47 is positioned at the base of the cornea 32. This area ofcircumferential placement is the foundation of the cornea and as suchthe structural base of the cornea 32. The properties of the materialsutilized for the ocular stent 47 and the O-ring 48 along with the amountof tensioning can be manipulated to create some movement of the O-ring48 with accommodative stimulation. This motion can be utilized toincorporate an accommodating anterior chamber interocular lens (ACIOL).

A front view of a preferred and non-limiting embodiment of a stent isshown in FIG. 6A. FIG. 6A illustrates placement of the continuous O-ring48 in the non-continuous variation of the collar stent 47 having ananterior aspect that is crenellated or notched. These crenellations 45have a similar function to the function of the beaded surface 15described previously. The crenellations 45 leave voids along the contactsurface, allowing for aqueous flow across the ocular stent 47. Theaqueous pressure does not depend on these crenellations 45 to equalizepressure. The void section of the ocular stent 47 would providesufficient flow on its own. The crenellations 45 of the ocular stent 47also serve the purpose of creating a non-continuous surface in contactwith the transition zone 42. Variations in the texture can bemanipulated to achieve optimization of the appositional stimulation ofstem cells. It would be possible to produce non-crenellated variations.Such variations would work similar to the ported version of thepreviously described embodiments of the stent 47. In this case the voidsection of the ocular stent 47 is oriented up to minimize transfer offree pigment and debris. This orientation is recommended forimplementations including, but not limited to, pigmentary glaucoma,pigment dispersion syndrome, and pseudoexfoliative glaucoma.

FIG. 6B is a sectional view of the ocular stent 47 with a sectional viewof the O-ring 48 in position. The ocular stent 47 is designed to allowfor some translation of movement induced by accommodative forces. FIG.6C is a partial side profile view of the ocular stent 47 as it would beviewed from inside the anterior chamber of the eye with the O-ring 48and crenellations 45 visible. The illustrated view orientating isindicated in FIG. 6A. Parts of the trabecular meshwork 17 anatomy willbe visible through the crenellations 45.

FIG. 7 is a detailed illustration of the invention showing a preferredand non-limiting embodiment of an ocular stent 47 in relation toadjacent anatomy. The stent 47 is assembled from multiple pieces ofthree components: anterior arms 50, posterior arms 51 and annular cords,such as beading lines 52 (shown in FIG. 8C). The arms 50, 51 connect ata joint 49, such as an articulating joint. The assembled componentscollectively create an articulating base. An O-ring 48 is positionedwithin the implanted articulating base. The stent 47 is implanted in theperipheral irideocorneal angle 44 of the anterior chamber, such that theanterior aspect of the anterior aim 50 is designed to be centered on andin contact with the surface of the transition zone 42 between theanterior limits of the trabecular meshwork 17 and posterior limits ofthe corneal endothelium 16 or posterior aspect of the limbus 41. Theanterior limits of the ocular stent 47 may encroach on and make contactwith the adjacent trabecular meshwork 17 and corneal endothelium 16. Theperipheral portion of the anterior arm 50 and peripheral portion of theposterior arm 51 are designed to be connected. This connection areaextends around the anterior chamber irideocorneal angle 44 to contactthe anterior chamber exposure of the ciliary body 27 up to or beyond thescleral spur 43 to encroach on the trabecular meshwork 17. The posteriorarm 51 is configured to be in contact with a portion of the surface ofthe peripheral iris 29. The central range of the posterior contact alongthe iris 29 will be sufficient to effectively support the ciliary body27 structure posterior to the iris 29. The stent 47 is configured toreposition and retain the position of the ciliary body 27. As shown inFIG. 7A, the stent 47 is well positioned anatomy to enable favourablefunction. The anterior arm 50 spans the filtering structure of thetrabecular meshwork 17 expanding and opening its porous structure. Thisstructurally supported configuration of the drainage anatomy willdecrease IOP and promote rejuvenation of the tissues. The anterior 50and posterior 51 arms of the ocular stent are to be composed of abiocompatible material that is relatively rigid. Polymethylmethacrylate(PMMA) is a suitable material; however, the ocular stent 47 componentsare not limited to PMMA. The material may have shape memorycharacteristics. As used herein, “shape memory” refers to a materialwhich returns to an initial shape when biasing forces are removedtherefrom. Shape memory may also refer to a material which returns to aninitial shape as a result of a triggering event such as when thematerial is heated to a specific predetermined temperature. Theincorporated O-ring 48 provides the ability to alter induced forces withrespect to the anatomical arrangement of the involved structures. Thecombination of components produces a stable structure able to articulateat the irideocorneal angle 44. The relatively stable properties alsoallow for consistent and accurate contact of the anterior arm 50 withthe transition zone 42. This contact is required to induce appropriateforces at this area of stem cell activity. The appositional stimulationof stem cells here can impact regeneration of corneal endothelial cells16 and cells pertaining to the trabecular meshwork 17. The anterior arm50 of the ocular stent is essential to the aforementioned actions on thetrabecular meshwork 17 and transition zone 42. This posterior contactalong the iris base 29 translates forces required to reposition theciliary body 27 and variable forces from muscular action in the ciliarybody 27 to the transition zone 42. The posterior repositioning shiftsthe accommodative structure posteriorly which in turn requires thestructures to expand circumferentially. This expansion translates into atightening of the posterior 38, equatorial 37, and anterior 36 zonules.The return of tension to these zonules results in some degree ofaccommodative function. The return of function will stabilize muscularaction by means of effective feedback and control of the ciliary body27. This is important as it relates to the hyaloid zonules 39. Theposterior movement of the ciliary body 27 relieves excessive tension onthe hyaloid zonules 39. This combined with returned control of theaccommodative musculature will relieve excessive tension beingtransferred to the hyaloid retinal connections and thus reduce the riskof retinal detachment. The stent 47 requires specific sizing andanatomical placement, but has significant adjustment because its multipiece construction and O-ring 48 component. For example, it is possibleto adjust the sizing of the stent 47 to induce forces to enable somemanipulation of refractive error. The ocular stent 47 is positioned atthe base of the cornea 32. This area of circumferential placement is thefoundation of the cornea and, as such, the structural base of the cornea32. The ability of stent 47 to articulate can enable it to harness andtranslate accommodative force to produce movement of the O-ring 48. Thismotion can be utilized to incorporate an accommodating anterior chamberinterocular lens (ACIOL).

A half section front view of the stent 47 is shown in FIG. 8A. The stent47 depicted in FIG. 8A illustrates the continuous beading together ofthe alternating anterior arm 50 and posterior arm 51 components.Placement of the O-ring 48 is also illustrated. The alternation of thecomponents produces voids, allowing for free aqueous flow throughout theocular stent. This is an advantage with respect to freedom of flow morerepresentative of the natural anatomy. In the case of pigment dispersionsyndrome and pigmentary glaucoma, this embodiment would not be thepreferred one. This configuration cannot provide any pre-filteringproperties as in the previously described embodiments of the stent. Thealternating structure also serves the purpose of creating anon-continuous surface in contact with the transition zone 42 and irisbase 29. The alternating pattern provides a variation of theappositional stimulation of stem cells.

FIGS. 8B and 8C are schematic views of the stent 47 in situ withillustrative anatomy. The relationship between the O-ring 48, theanterior arm 50, the posterior arm 51 and anatomy is shown for thepurpose of relating to FIG. 8C. FIG. 8C is a partial side profile viewof the stent 47 as it would be viewed from inside the anterior chamberof the eye with anatomy visible. The stent 47 has the advantage ofleaving some of the anatomy visible through the voids. It is noted thatall of the embodiments of the stent described herein can be viewed bygonioscopy; however, the stent 47 depicted in FIGS. 7-8D has the mostanatomy visible. The partial side view of the components has beenstaggered to illustrate the relationship between the components. Thisview best illustrates that the beading lines 52 tie the componentstogether. As shown in FIG. 8C, three beading lines 52 are required toassemble the components. The triplication provides security that thisembodiment will remain intact once assembled. FIG. 8D illustrates sideand front views of the anterior arm 50 and posterior arm 51 separated asindividual units. The holes used for beading are shown. The anterior arm50 has three round holes 53, while the posterior arm has two round holes53 and one slotted hole 54. The purpose of the slotted hole 54 is toallow articulating but limit range of motion. Such a limit on the rangeof motion is required to prevent the ocular stent from folding in onitself during implantation. The arms of the ocular stent 47 must remainopen enough to insert the O-ring 48.

FIG. 9A is a sectional view of an aphakic eye illustrating the stent 47with an articulating joint 49. The implantation of an accommodatingACIOL is illustrated as it would be implanted and fit to the stent 47.The ACIOL body 57 illustrates the positioning of the ACIOL when theaccommodative musculature is relaxed and 57′ illustrates the ACIOL'schange in position and curvature under accommodative stimulus.Articulation of the posterior arm 51 translates the accommodativecontractions into small amounts of movement of the O-ring 48′. TheO-ring 48′ is incorporated into the ACIOL design becoming the peripherallimits of the ACIOL. The O-ring 48′ is circumferentially fused with theextended anterior surface 55 of the ACIOL. The ACIOL has its opticalform completed by its posterior surface 56. The two surfaces of theaccommodating ACIOL could be manufactured from acrylic material that isthen filled with index matched silicone oil or material of similarproperties. These material properties will enable the vaulted ACIOL tochange curvature with minor movement. Model tests and calculationsindicate a decrease in diameter of 200 microns would potentially induce10 diopters of accommodation. The refractive power of the ACIOL willneed to be greater than the power of the human lens to producesufficient levels of accommodation. In order to create an effectiveoptical system of the appropriate total power a PCIOL 58 of opposingpower will be required to complete this dual optic design.

FIG. 9B illustrates frontal view of the anatomy and the stent 47 with anaccommodating ACIOL. The view is divided into quarters A, B, C, D. Thefirst quarter A illustrates this embodiment independent of any anatomy.The alternating anterior arms 50 and posterior arms 51 along with theO-ring 48 are visible. The second quarter B represents the ocularanatomy without any stents implanted. The third quarter C illustratesthe complete system of the stent 47 and the accommodation ACIOLcomponents. Components visible would include partial views of theanterior 50 and posterior 51 arms. Although predominantly clear, thebody of the ACIOL 57 and its anterior 55 and posterior 56 surfaces wouldbe in view. The fourth quarter D has the complete assembly of componentsillustrated with the anatomy removed. An artificial pupil ring isindicated by 59. Because the optics of the ACIOL are anterior to thenatural pupil it is optically advantageous to create a boundary betweenthe refractive and non refractive aspects of the ACIOL.

FIG. 10A is an exemplary injector. Generally, the injector consists of amain body 60 that houses the plunger mechanism 62. The plunger has asilicon stopper 63, which is required to create the hydraulic pressureof the viscoelastic gliding agent used to eject the folded stent 18, 47and/or the folded O-ring 48 from the chamber. The injector cartridge 61opens allowing the ocular stent 18, 47 to be positioned carefully andflooded with viscoelastic before folding. In this illustration theO-ring 48 is being prepared for implantation. It may be required to pushpart of the O-ring 48 in to the cartridge tip 61′ prior to folding. Thiswill depend on the length of the cartridge tip 61′.

In FIG. 10B a front view of the implantation procedure is illustrated.Here the eye has been prepared with eyelid speculums 64 in place and theincision wound 65 made. This illustration shows the stent 47 with itsbase structure already implanted. The anterior 50 and posterior 51 armsare partially visible in the anatomy, but clearly visible in the sectionwhere the anatomy has been removed for illustrative purposes. The O-ring48 is seen as it is ejected from the cartridge tip 61′. The plunger 62and the silicone stopper 63 creating the hydraulic viscoelastic pressureare also visible.

Discussion of this invention is made in relation to the human eye, butit is appreciated that the invention described herein is not limited orexclusive of the human eye. While specific embodiments of the inventionhave been described in detail, it will be appreciated by those skilledin the art that various modifications and alternatives to those detailscould be developed in light of the overall teachings of the disclosure.Accordingly, the particular arrangements disclosed are meant to beillustrative only and not limiting as to the scope of invention which isto be given the full breadth of the claims appended and any and allequivalents thereof. Further, although the invention has been describedin detail for the purpose of illustration based on what is currentlyconsidered to be the most practical and preferred embodiments, it is tobe understood that such detail is solely for that purpose and that theinvention is not limited to the disclosed embodiments, but, on thecontrary, is intended to cover modifications and equivalent arrangementsthat are within the spirit and scope of the appended claims. Forexample, it is to be understood that the present invention contemplatesthat, to the extent possible, one or more features of any embodiment canbe combined with one or more features of any other embodiment.

What is claimed is:
 1. An annular ocular stent for insertion in anirideocorneal angle of an anterior chamber of an eye comprising: aplurality of anterior arms configured to contact a surface of atransition zone between a trabecular meshwork and a corneal endotheliumof the eye; and a plurality of posterior arms configured to contact aperipheral iris of the eye, a central portion connecting the anteriorarms and the posterior arms to form an articulating joint with thecentral portion being a point of rotation, thereby defining an interiorangle and an exterior angle, the exterior angle being commensurate withand configured to fit within the irideocorneal angle of the eye; and ano-ring adjacent to and receivable within the interior angle defined bythe anterior and posterior arms.
 2. The stent of claim 1, wherein thecentral portion comprises an annular cord, wherein at least one of theposterior arms and the anterior arms defines at least one through holeand wherein the cord is inserted therethrough, thereby connecting the atleast one arm to the cord.
 3. The stent of claim 2, wherein at least oneof the through holes is a slotted through hole for limiting the range ofmotion of the joint.
 4. The stent of claim 2, wherein the anterior armsand the posterior arms alternate along the one cord.
 5. The stent ofclaim 1, wherein the plurality of anterior arms are also configured tocontact at least a portion of an anterior portion of the trabecularmeshwork.
 6. The stent of claim 1, wherein the plurality of anteriorarms comprise a plurality of crenellations extending therefrom, thecrenellations being configured to create non-continuous contact with thetransition zone.
 7. The stent of claim 1, wherein a portion of each ofthe plurality of posterior arms is configured to extend around theirideocorneal angle and cross an anterior chamber exposure of a ciliarybody up to or beyond a scleral spur of the eye.
 8. The stent of claim 1,wherein the plurality of posterior arms are configured to be in contactwith a portion of a surface of the peripheral iris.
 9. The stent ofclaim 1, wherein the plurality of anterior arms and the plurality ofposterior arms comprise one or more of: polymethylmethacrylate (PMMA),silicone or acrylic block polymers materials having PMMA components,hydrophobic acrylics, hydrophilic acrylics, acrylicpoly(styrene-block-isobutylene-block-styrene), silicon elastomer, andheparin surface modified acrylics.
 10. The stent of claim 1, wherein theplurality of anterior arms and the plurality of posterior arms comprisea shape memory material.
 11. The stent of claim 1, further comprising ananterior chamber interocular lens coupled with the o-ring.